Specializing interpreter for python perf demo code.

mikeckennedy · mikeckennedy · commit bdb66debe804 · 2022-12-21T13:32:41.000-08:00
diff --git a/code/ch05-perf/specialize_final.py b/code/ch05-perf/specialize_final.py
@@ -0,0 +1,55 @@
+import datetime
+import math
+
+
+def f_to_c(f: float) -> float:
+    """Convert Fahrenheit to Celsius."""
+    x = f - 32.0
+    return x * (5 / 9)
+
+
+def c_to_f(c: float) -> float:
+    """Convert Celsius to Fahrenheit."""
+    x = c * (9 / 5)
+    return x + 32.0
+
+
+TEST_VALUES = [-459.67, -273.15, 0.0, 32.0, 42.0, 273.15, 100.0, 212.0, 373.15]
+
+
+def test_conversions() -> None:
+    for t in TEST_VALUES:
+        assert_round_trip(t)
+
+
+def test_speed():
+    count = int(1_000_000 / len(TEST_VALUES))
+    for _ in range(0, count):
+        for t in TEST_VALUES:
+            round_trip(t)
+
+
+def round_trip(t: float) -> float:
+    return f_to_c(c_to_f(t))
+
+
+def assert_round_trip(t: float) -> None:
+    # Round-trip Fahrenheit through Celsius:
+    assert math.isclose(t, f_to_c(c_to_f(t))), f"{t} F -> C -> F failed!"
+    print(f'{t:,.1f} F -> {f_to_c(t):,.1f} C')
+    # Round-trip Celsius through Fahrenheit:
+    assert math.isclose(t, c_to_f(f_to_c(t))), f"{t} C -> F -> C failed!"
+    t2 = f_to_c(t)
+    print(f'{t2:,.1f} C -> {c_to_f(t2):,.1f} F')
+    print()
+
+
+if __name__ == "__main__":
+    t0 = datetime.datetime.now()
+
+    # test_conversions()
+    test_speed()
+
+    t1 = datetime.datetime.now()
+    dt = t1 - t0
+    print(f'Done in {dt.total_seconds() * 1000:.2f} ms')
diff --git a/code/ch05-perf/specialize_start.py b/code/ch05-perf/specialize_start.py
@@ -22,6 +22,13 @@ def test_conversions() -> None:
         assert_round_trip(t)
 
 
+def test_speed():
+    count = int(1_000_000 / len(TEST_VALUES))
+    for _ in range(0, count):
+        for t in TEST_VALUES:
+            round_trip(t)
+
+
 def round_trip(t: float) -> float:
     return f_to_c(c_to_f(t))
 
@@ -40,7 +47,8 @@ def assert_round_trip(t: float) -> None:
 if __name__ == "__main__":
     t0 = datetime.datetime.now()
 
-    test_conversions()
+    # test_conversions()
+    test_speed()
 
     t1 = datetime.datetime.now()
     dt = t1 - t0
